Presentation is loading. Please wait.

Presentation is loading. Please wait.

Modification of the Prolyl Ring of Val-Pro-Ala and the Impact of this Modification on b 2 Ion Structure Matthew Bernier, Julia Chamot-Rooke, Ashley Gucinski,

Similar presentations


Presentation on theme: "Modification of the Prolyl Ring of Val-Pro-Ala and the Impact of this Modification on b 2 Ion Structure Matthew Bernier, Julia Chamot-Rooke, Ashley Gucinski,"— Presentation transcript:

1 Modification of the Prolyl Ring of Val-Pro-Ala and the Impact of this Modification on b 2 Ion Structure Matthew Bernier, Julia Chamot-Rooke, Ashley Gucinski, & Vicki Wysocki International Symposium on Molecular Spectroscopy 68th Meeting 6/19/13

2 Roepstorff P, Fohlman J. Biomed. Mass Spectrom. (1984) 11 (11): 601. b2b2 y2y2 b fragment ion formation Collision induced dissociation (Ar/He)

3 oxazolone diketopiperazine cis trans b fragment ion formation

4 VS Isomerization (trans-cis) Rel. Energy 20 kcal/mol 13 kcal/mol JACS, 1988. 110(13): p. 4212-4216. 2.5 kcal/mol 0.5 kcal/mol What makes proline so special?

5 Gucinski et al. Phys Chem A 2013. – Just Accepted Only ONE of the XxxPro peptides here show no evidence of diketopiperazine b 2 structure What makes proline so special?

6 Collagen Triple Helix: Substituent stability Biopolymers, Vol. 59, 24–28 (2001) PNAS ∣ January 12, 2010 ∣ vol. 107, 559–564 ProHypGly ProProGly 30.5 °C 36 °C TmTm

7 Collagen Triple Helix: Substituent stability PNAS ∣ January 12, 2010 ∣ vol. 107, 559–564 34 °C 58 °C TmTm

8 J. Org. Chem. 2004, 69, 8565-8573. J. Am. Chem. Soc., Vol. 123, No. 4, 2001 Effects of prolyl ring substitution X = H, OH, or F Y = H X = H Y = OH or F

9 J. Org. Chem. 2004, 69, 8565-8573. Can we influence oxazolone/diketo prevalance with substituent influence on trans/cis isomerization barrier? Effects of prolyl ring substitution

10 Does wavelength excite vibrational mode of molecule? Yes Fragmentation Efficiency No + No fragments = no intensity @ wavenumber scanned + Molecule of interest ionized into the gas phase + MS trapping and irradiation with tunable IR laser Electrospray Ionization (ESI) Fragmentation Efficiency: I fragments / I precursor + + OR Fragment ions detected- measurable intensity at vibrationally active energy CLIO Infrared Laser Tunable 1000-2000 cm -1 Action Infrared Multi-Photon Dissociation Spectroscopy

11 K trans/cis = 4.6 ValXxx Vibrational Spectroscopy - ValPro Gucinski, A. C.; Chamot-Rooke, J.; Steinmetz, V.; Somogyi, A.; Wysocki, V. H. J Phys Chem A 2013, 117, 1291.

12 ValXxx Vibrational Spectroscopy – Val(Y-Flp) K trans/cis = 6.7 J. Org. Chem. 2004, 69, 8565-8573.

13 ValXxx Vibrational Spectroscopy – Val(X-Flp) K trans/cis = 2.5 J. Org. Chem. 2004, 69, 8565-8573.

14 ValXxx Vibrational Spectroscopy K trans/cis = 2.5 K trans/cis = 4.6 K trans/cis = 6.7 Gucinski, A. C.; Chamot-Rooke, J.; Steinmetz, V.; Somogyi, A.; Wysocki, V. H. J Phys Chem A 2013, 117, 1291. X-Flp Y-Flp Pro x10 x25 x50

15 Gas phase vs. solution phase structure

16 Y-FlpX-Flp Oxazolone Diketopiperazine

17 Tandem MS 3 comparison: V(Xflp) vs V(YFlp) Oxazolone Diketopiperazine

18 Conclusions Holds true in gas phase

19 Acknowledgments NIH GMR01-51387


Download ppt "Modification of the Prolyl Ring of Val-Pro-Ala and the Impact of this Modification on b 2 Ion Structure Matthew Bernier, Julia Chamot-Rooke, Ashley Gucinski,"

Similar presentations


Ads by Google